This invention relates to material handling systems and, in particular, warehousing systems for steel bars or tubing, aluminum bars or tubing, alloy steel bars, and other like elongated articles. The lengths of such items may range, for example, from twelve to twenty feet. Industry has for some time changed its primary concern in storage systems from area to volume considerations. This principle has resulted in frequent use of stacker systems for storage. A stacker system includes a framework forming a rack having a series of standard-sized pockets or cubicles. Containers or trays designed to fit into the pockets of the rack hold the stored articles. The stacker system is served by either an overhead crane or a mobile lift truck high mast unit to deposit and retrieve particular trays. While the rack and its trays may be variously sized for different applications, a typical tray size for storage of rod and tube stock is twenty-four inches wide by eight inches high by nine feet long. Between five thousand and ten thousand pounds of steel may be stored in such a container.
Each container contains bars or tubing separated according to type, size and length. The trays are located in the stacker system in an organized, systematic pattern. Allowances are made for clearances between the trays. When trays are made up, the preferred arrangement is to have both ends of the stock squared and also to have the stock central to the tray. When the trays are filled and squared they are located in the rack system with clearance. Stock that is not squared may not fit in an assigned pocket; a tray with stock that is staggered instead of squared (on either end or both) may interfere with movement of other trays into and out of adjacent positions in the rack.